I somehow managed to solve the problem of the serial flash memory write block size vs. the erase block size. I just had to write a custom FAT12 filesystem..

As seen before, the Temperature Logger will act like an USB memory stick. There will be at least two files. One with the time stamped temperature measurements and one file allowing the user to set the logger’s configuration.

The configuration file must be accessible by any OS and modifiable. It will configure the temperature measurement period, from one every second till one every 24h (86400 seconds), in seconds. It’s also used to synchronize the PIC’s real time clock and calendar to the computer’s current time and date.

for more detail:Pick and Place